downs



J. E. DOWNS MACHINE FOR STACKING FLAT SHEETS OF MATERIAL 4 Sheets-Sheet 1 F eb. 7, 1956 Filed Aug. 26., 1952 INVEN TOR.

Feb. 7, 1956 J. E. DowNs 2,733,921

MACHINE FOR STACKING FLAT SHEETS OF MATERIAL FiledAug. 26, 1952 4 Sheets-Sheet 2 IN VEN TOR.

Feb. 7, 1956 .1. E. DowNs 2,733,921

MACHINE FOR STACKING FLAT SHEETS OF' MATERIAL Filed Aug. 26, 1952 4 Sheets-Sheet 5 IN VEN TOR.

Feb. 7, 1956 J. E. DowNs 2,733,921

MACHINE FOR STACKING FLAT SHEETS 0F MATERIAL Filed Aug. 26, 1952 4 Sheets-Sheet 4 s Zitpl- IN VEN TOR.

United States Patent MACHINE FOR STACKING FLAT SHEETS F MATERIAL John E. Downs, Tippecanoe, Ind., assignor to The Union Tool Corp., Warsaw, Ind., a corporation of Indiana Application August 26, 1952, Serial No. 306,402 11 Claims. (Cl. 271-68) The present invention relates to a machine for stacking at sheets of material such for example as metal plates. 1

In many commercial operations relatively large sheets of metal are handled and subjected to varied treating processes which require their repeated handling and particularly their collection in suitable stacks, deposited upon pallets or other supporting means.

In the handling of such sheets it is often quite important thatl their surfaces, either one or both, be not unduly marred or scratched so that the article subsequently manufactured from the sheets will not be defective. This, for example, is true in the automotive industry in preparing sheets from which car bodies are to be made, and also in the fabrication of refrigerators, metal cabinets, and the like, in which the sheets are often prepainted or otherwise decorated. Moreover, in some industries the sheets have to be subjected to various rust preventing treatments, tempering, heat treating, and the like.

The present invention is particularly concerned with the handling of sheets which are being discharged seriatim from a sheet treating instrumentality such as a spray painting oven, heat treating oven, polishing machine, or the like.

It is one of the objects of the present invention to provide a machine which will receive individual sheets which are being fed to` it out of a machine or by means of a suitable conveyor which sheets are then advanced to a given position and then accurately dropped to eventuate a stack thereof.

It is a further object of the present invention to provide a machine of the character just stated in which the sheets, prior to reaching their inal position, and just prior to dropping them into a stack, are so conveyed that they will not deviate laterally from a predetermined path.

It is a further object of the present invention to provide a machine in which sheets may be accurately advanced, accurately dropped and guided to form a neat parallel sided stack of sheets.

It is still a further object of the present invention to provide a machine of the character indicated above with temporary supporting means for a small number of sheets after they have been advanced and dropped so as to afford time for the taking away of a previously formed stack and the placement of a suitable stack-receiving instrumentality such as a pallet, truck or the like.

Other objects of the present invention will become manifest from a perusal of the drawings furnished herewith and the further description of the invention hereinbelow.

In the drawings:

Fig. l is a perspective end view of the completely assembled machine of thepresent invention.

Fig. 2 is a side elevation thereof;

Fig. 3 is a top plan view of the machine in a certain position where the transporting mechanism is as close together as the machine will permit;

Fig. 4 is an end view with many of the parts removed and showing the essential operating mechanism; and

Fig. 5 is a similar View with still further parts omitted Jlee in order to diagrammatically illustrate the operation of the essential working parts of the machine.

ln essence the machine comprises a frame upon which are mounted two opposed sets of conveyors each consisting of a series of horizontally extending tapered rollers which are mechanically driven and which serve to support sheets of metal near the edge portions thereof so that, as a result of the motion of these rollers, the sheets will be advanced from the entrance of the machine to the exit thereof. As soon as the sheets have reached a given position they contact a suitable switch which in turn actuates certain compressed gas operated reciprocating motors such as air cylinders which serve to swing the horizontally disposed rollers toward a substantially vertical position so that the sheets will drop under the inlluence of gravity and become desposited upon a suitable pallet or the like.

Means are also provided for guiding the sheets while they are dropping so that they will eventuate an accurate and neat pile.

Means are also provided for temporarily supporting a number of sheets while the pallet containing the stack is removed and replaced by an empty one, all this for the purpose of enabling the continuous operation of the machine.

T he machine itself is supported upon a framework 6 to which are bolted the main operating parts of the machine. Supported at about' the middle of the machine upon a central and longitudinally thereof extending I- beam 7 is the air cylinder operating mechanism 8 and also the electric motor 9 which serves to actuate the various moving parts.

As can best be seen in Figs. l and 3, there are suitably supported upon channels 10 a plurality of tapered transporting rollers 11 there being two opposed sets thereof, the rollers being relatively staggered to each other as is apparent from Fig. 3.

The channel frame works 10 are capable of being moved away from and toward each other upon the transversely extending end pieces 12 of the machine so that the distance between the two sets of rollers may be varied, in accordance with the Width of the sheets which are to be transported thereon. These channels 1t) are moreover interconnected with each other by means of diagonally extending braces 13 in order to give the necessary rigidity to the machine. The rollers themselves are aixed to gear boxes 14, there being one of these for each of the rollers 11 and these gear boxes 14 are in turn pivoted so as to be swingable about a horizontal axis which runs longitudinally of the machine so that the gear boxes and the rollers 11 may be tilted from a substantially horizontal position as shown in Figs. 1, 2, 3 and 4 to the changed position shown in Fig. 5.

All of these gear boxes 14 are connected to a single shaft so that may be simultaneously turned from a horizontal to an almost vertical downwardly extending position, this being accomplished by means of the air cylinders 15, which are connected with the shaft by a suit able rod 16, the end of which is aixed to the gear box 14 by the connections 17. in order to impart a corresponding tilting movement to the gear boxes 14 on the opposed set of rollers, these are connected as can best be appreciated from a study of Fig. 5 by means of the chain belt 18, which is kept under the proper tension by means of the sprocket wheels 19, 20, 2l, 22 and 23. The reason for providing these adjusting sprockets is by rea son of the fact that it is necessary to adjust the distance between the opposed sets of rollers to correspond with the width of the sheets which are being'transported. The gears within the boxes 14 and hence therefore the rollers 11 are actuated by means of the electric motor 9 through the intermediation of chains 24 which are driven by sprockets 25 on the motor. It will be understood that the motor may be provided with a reducing gear box 26 as is well known, in order to control the speed of the mechanism. The gear box may in turn be driven by means of the belt 27 as can best be seen in Figs. 2 and 3, the motor being mounted on an adjustable mounting 2S, the position of the motor being controlled by means of the screw 29 actuated by the hand wheel 3).

The various gear boxes are connected one to the other by means of chains 3l. The air cylinder 15 contains the usual cylinder and reciprocating piston means being provided for alternately introducing and exhausting air from in front of and behind the cylinder, as is well known in the art. Suitable piping which may be ilexible rubber piping 32 serves to supply the air cylinders. There are also provided suitable solenoids for actuating the main control air cylinder 8 which in effect is a master valve for the various cylinders; the valves therein which are of the usual construction and hence need no illustration being operated by solenoids which are in an electrical circuit in series with a number of switches. One of these switches 33 is located at the discharge end of the machine (see right hand side of Fig. 2). This switch is so arranged that when an advancing sheet hits it, it will close an electrical circuit which actuates the proper solenoid so as to allow compressed air to enter the correct side of the air cylinder 15 whereby it will push up on the end of the gear boxes le so as to swing the rollers 1i downwardly, this motion being transmitted to the opposed gear box by means oi the chain belt it?, as already fully described.

As the gear box swings down it hits the contact peint of a second electrical switch 34 (see Fig. 5) which actuates the solenoid so that the air is now admitted to the top of the cylinder within the air cylinder 15 so that the rod 16 will be pulled down and the rollers restored almost immediately to their horizontal position; The action is quite rapid and just enough time elapses to permit the sheet to drop under its own weight.

As can best be seen from the end view in Fig. 4, a sheet 3S which may be of metal or the like, is supported at its longitudinal sides on the rollers 11. The taper on these is preferably so arranged that the slight amount of sag which naturally occurs at the longitudinal center of the sheets will give the sides of the sheet a direction so that they will contact substantially the entire peripheral rotating surface of the rollers 11. If the rollers, instead of being tapered were made straight, then only the edges of the rollers would have engaged the sheets and tte rest of the sheets at the edge portions would be out in open space. of support, and this would be very liable to mar the sheets, particularly if they had been painted or decorated.

There is also another very impotrant advantage in having the rollers tapered instead of straight; by tapering them the sheets will automatically be centered between the two opposed sets of rollers, and if they tend to wander in either direction from the longitudinal axis of travel, the increased peripheral speed which one side would be given as compared with the other side of the sheet would immediately recenter the sheet so that it would travel straight. Moreover by having the rollers comparatively long, the machine does not need to be adjustcd nearly as much as would be the case if the rollers were straight.

As shown in Figs. 4 and 5, the sheet 35 will drop as soon as the rollers attain the position shown in Fig. 5, and will then fall upon the pallet 36 forming a stack 37 thereon.` In order that the sheets may be properly guided to keep them from swaying sidewise during their fall, there are provided the laterally longitudinally ex" tending guides 38, the position of which is adjustable through the intermediation of the chains 39 and 48, which are operated through suitable gears which do not appear on the drawings.

In order to provide for the continued operation of the In other words, there would only be two points machine during the time a pallet is removed and replaced by an empty one, temporary storage means are present in the form of reciprocatable rods 41. These are housed in air cylinders 42 so that they may be thrust out into the space beneath the rollers 11. For sake of simplicity these rods 14 have been omitted from Fig. 5, but they are shown in Figs. 1 and 4. These cylinders 42 are connected by suitable rubber piping 43 and 44 through which air may be admitted through the control valve 45 which is hand operated by means of the outwardly extending lever e6. Therefore whenever a truck comes along to remove the pallet 36, the operator, by depressing the lever 46 and holding it, can cause the rods 4l to assume the position shown in Fig. l so that thc plates will be tcmporarily supported.

ln order to atord a complete clearance of the tapered rollers 11, when they are in their downward position, they are retracted through the spaces or cut-outs 47 which are visible however only in Fig. 2.

The machine operates as follows:

Sheets enter the machine, for example, through the slot 48 and travel in the direction away from the slot by reason of the rotation of the rollers 11, the sheet 35 being supported thereon substantially in the manner shown in Fig. 4. In other words, there is a slight sag in the middle of the sheet. Of course, if the sheets are very rigid this sag may be almost imperceptible but with the thinner sheets it is definitely there, and is one of the reasons for the taper of the rollers 11. As the sheet advances through the ma chine, the forward end of it will eventually contact thc switch 33 which causes, through the intermediation of the action of the solenoid, the air valve, and the air cylinders, the rollers 11 to assume the downward position so as to drop the sheets. A sheet in such a condition of free drop is illustrated in Fig. 5.

The sheets will accumulate on the pallet 36 in the form of a pile 37, unless during the removal of the pallet and the replacing of a new one, the temporary supporting rods 41 serve to support the sheets.

Immediately upon the rollers and the gear boxes 14 assuming the lower position, they contact the switch 34 which reverses the air valve and immediately restores the rollers to the horizontal position.

Applicant is aware of the fact that sheet stacking devices of this general order have been known, but they all suier from the defects that the sheets would not travel straight and that no provisions were made to allow for the unavoidable sag when handling thinner sheets. Moreover, the prior art devices, such as are known to applicant, do not provide for automatic centering of the sheets through their travel through the machine nor for the rapid return of the supporting rollers or other instrumentalities, and particularly do they not provide for the uninterrupted operation during the changing of a pallet or other device for receiving the dropped sheets.

The exact position of the various parts are of course open to considerable variation, and the drawings and the description are to be therefore considered in the nature of a general example illustrating the novel features of the apparatus.

Applicant claims:

l. A machine for stacking sheets of llat material which comprises a frame, two sets of horizontally disposed tapered rollers located opposite each other with the rollers of one set being offset relative to the rollers of the opposite set, said rollers being pivotally supported at one end and tapered toward their free ends, means for positively driving said rollers to advance sheets while supported thereon along their edge portions, means for quickly changing the position of said sets of rollers from horizontal to steeply downwardly inclined to effect release and consequent dropping of said sheets, means for returning said sets of rollers to their original horizontal position and actuated by contact of the roller-tipping mechanism with said means when the rollers are in their lowest position, and

means for laterally guiding dropped sheets to a supporting means.

2. In a machine as defined in claim 1, means for varying the horizontal distance between the opposed sets of rollers.

3. A machine for stacking flat sheets comprising a frame, two sets of pivoted tapered rollers located horizontally opposed to each other, means for positively driving said rollers to advance a sheet supported thereon, compressed gas operated reciprocating motors for pivoting said sets of rollers to cause them to assume a downwardly steeply inclined position to effect release and dropping of a sheet and for returning them to their original horizontal position, a supply of compressed gas, solenoid-operated valves for controlling said reciprocating motors by admitting compressed gas to alternate sides of the pistons therein, an electrical circuit for actuating said solenoids, and limit switches contacted, respectively, by the near end of an advancing sheet and by the rollers at their lowest point for controlling said circuit.

4. A machine as defined in claim 3 provided with separately and independently actuated temporary sheet-supporting members beneath the rollers, and actuatable by means of said compressed gas.

5. A machine for stacking bendable sheets which comprises a frame, two sets of horizontally positioned opposed sets of staggered driven rollers pivotally supported at one of their ends and tapered toward their free ends sufficiently to support the edge portions of the sheets even though they sag at their unsupported longitudinal central portions, means for driving said rollers to advance a sheet thereon, pivoted supporting means for said rollers, reciprocating compressed air driven motors connecting with said pivoted supporting means for turning the axes of said rollers from a horizontal to a downwardly inclined position so as to release and drop the sheets, means, including an electrical switch actuated by contact with the advancing end of an advancing sheet to effect said pivotal movement, means including a second electrical switch operated by contact with the pivoted supporting means whereby to restore the axes of the rollers to their horizontal position, means for varying the horizontal distance between the sets of rollers, and guide means for laterally guiding dropped sheets to evenutate a pile thereof.

6. A machine as defined in claim 5 provided with separately, selectively operated means for receiving dropped sheets, said means being positioned below said rollers, and being controllably retractable to further drop the temporarily supported sheets to eventuate a stack thereof.

7. A machine as defined in claim 6 in which the temporary supporting means are operative through suitable openings in the guide means.

8. A machine for conveying flat sheets and stacking them into an even pile upon a suitable support comprising an elongated framework, and, supported thereon, the combination of two sets of longitudinally extending horzontally opposed sheet-conveying means comprising tapered driven rollers terminally swingable about a horizontal axis which is normal to the axis of rotation of said rollers, said rollers being tapered toward their free ends, means for swinging said rollers downwardly out of their horizontal sheet-supporting position and for immediately thereafter restoring them to their original horizontal position, said means comprising cylinders having compressed gas actuated pistons thereon operatively connected with the swinging means, valves for alternately applying gas pressure to opposite sides of said pistons, said valves be,- ng electrically operated by solenoids located in an electrical circuit in series with switches actuated, respectively, by contact with the end of a conveyed sheet when it reaches a. predetermined position and by the swinging means when the latter reach their downmost position.

9. A machine for conveying at sheets and stacking them into an even pile upon a suitable support comprising an elongated framework and, supported thereon, the

combination of two sets of longitudinally extending horizontally opposed sheet-conveying means comprising tapered driven rollers terminally swingable about a horizontal axis which is normal to the axis of rotation of said rollers, said rollers being tapered toward their free ends, means for swinging said rollers downwardly out of their horizontal position and for immediately thereafter restoring them to their original horizontal position, said means comprising cylinders having compressed-gasactuated pistons thereon operatively connected with the swinging means, valves for alternately applying gas pressure to opposite sides of said pistons, said valves being electrically operated by solenoids located in an electrical circuit in series with switches actuated, respectively, by contact with the end of a conveyed sheet when it reaches a predetermined position and by the swinging means when the latter reach their downmost position, and laterally horizontally reciprocable temporary sheetsupporting means for holding sheets before their being deposited upon a sheet stack pallet.

l0. A machine for conveying flat sheets and stacking them into an even pile upon a suitable support comprising an elongated framework, and, supported thereon, the combination of two sets of longitudinally extending horizontally opposed sheet-conveying means comprising tapered driven rollers terminally swingable about a horizontal axis which is normal to the axis of rotation of said rollers, means for swinging said rollers downwardly out of their horizontal position and for immediately thereafter restoring them to their original horizontal positions, said means comprising cylinders having compressed-gas-actuated pistons thereon operatively connected with the swinging means, valves for alternately aplying gas pressure to opposite sides of said pistons, said Valves being electrically operated by solenoids located in an electrical circuit in series with switches actuated, respectively, by contact with the end of a conveyed sheet when it reaches a predetermined position and by the swinging means when the latter reach their downmost position, laterally horizontally reciprocable temporary sheet-supporting means for holding sheets before their being deposited upon a sheet stack pallet, and means for laterally guiding the dropped sheets to form a pile thereof.

1l. In a machine for receiving and piling at metal sheets the improvements which comprise receiving, conveying and dropping means including two swingable opposed roller-supporting means, sets of horizontally positioned co-planar rollers supported at one end on said means, said rollers being tapered toward their free ends, means for adjusting the distance between said free ends, means for positively rotating said rollers to cause them to advance sheets resting thereon with their marginal portions, means for simultaneously tilting all of said rollers downwardly to effect release of said sheets, and means, operated by contact of the supporting means therewith at their points of lowest position, for restoring the rollers to their original horizontal position.

References Cited inthe file of this patent UNITED STATES PATENTS 281,150 Smith July l0, 1883 1,650,037 Phillips Nov. 22, 1927 1,727,209 Leutz Sep. 3, 1929 1,951,178 Smitmans Mar. 13, 1934 2,071,682 Buccicone Feb. 23, 1936 2,164,371 Ajello July 4, 1939 2,257,469 Keil Sep. 30, 1941 2,315,003 Martin Mar. 30, 1943 2,320,094 Nash May 25, 1943 2,333,479 Graf Nov. 2, 1943 2,375,241 Lindgren May 8, 1945 2,414,059 Powers Jan. 7, 1947 2.626,800 Martin Jan. 27, 1953 2,633,357 Rooney Mar. 31, 1953 

